For Maxima and minima just take derivitinima!
Happiness, now just assess the zero, zero, zero, zero!
Don’t forget you must inspect the endpoints as they are suspect!
Find the values of our function, look for Highs and Lows!

Local Maxima are on an Interval,
Local Minima are on an Interval!
Global Maxima aren’t on an Interval,
Global Minima aren’t on an Interval!
-terval! -terval! -terval!

Saddle, Peak and Trough and
Saddle, Peak and Trough and
Saddle, Peak and Trough and
Peak and Trough and
Peak and Trough and
Saddle, Peak and Trough and
Saddle, Peak and Trough and
Saddle, Saddle,
Peak and Trough and
Peak and Trough.

and!
Saddle, Peak and Trough and
Saddle, Peak and Trough and
Saddle, Peak and Trough and
Peak and Trough and
Peak and Trough and
Saddle, Peak and Trough and
Saddle, Peak and Trough and
Saddle, Saddle,
Peak and Trough and
Peak and Trough.

Now Maxima and minima
are also called the extrema,
Sometimes they can be absolute
as long as there’s no greater, lesser,
Relative implies a region that the extremum is in.
DON’t confuse a saddle point!
With an Extremum!

Local Maxima are on an Interval,
Local Minima are on an Interval!
Global Maxima aren’t on an Interval,
Global Minima aren’t on an Interval!
-terval! -terval! -terval!

Saddle, Peak and Trough!